Novel group IV metal precursors and a method of chemical vapor deposition using the same

ABSTRACT

An organometallic precursor of a formula M(L) 2  for use in formation of metal oxide thin films, in which M is a group IV metal ion having a charge of +4 and L is a tridentate ligand having a charge of −2, the ligand being represented by the following formula (I):  
                 
 
     wherein each of R 1  and R 2 , independently, is a linear or branched C 1-8  alkyl group; and R 3  is a linear or branched C 1-8  alkylene group. Also disclosed is a chemical vapor deposition method wherein a metal oxide thin film is formed on a substrate using the organometallic precursor. The precursor exhibits excellent volatility, thermal property and hydrolytic stability and is particularly suitable for the deposition of a multi-component metal oxide thin film containing a group IV metal such as titanium.

BACKGROUND OF THE INVENTION

[0001] Priority Korean Patent Application Nos. 2000-49832 filed Aug. 26,2000 and 2001-2574 filed Jan. 17, 2001, are incorporated herein in theirentirety by reference.

[0002] 1. Field of the Invention

[0003] The present invention relates to a novel group IV metal precursorand to a chemical vapor deposition method using the precursor. Moreparticularly, the present invention relates to a chemical vapordeposition method which comprises forming a metal oxide thin film on asubstrate using a group IV metal precursor which contains a tridentateN-alkoxy-β-ketoiminate ligand having a charge of −2.

[0004] 2. Description of the Prior Art

[0005] With development in the telecommunication industry, there is anincreased need for the development of new electronic materials. Also, aselectronic devices are continuously reduced in both size and thickness,it has become important to advance metal oxide processing technologiesand, in particular, thin film formation technologies.

[0006] A Metal-Organic Chemical Vapor Deposition (MOCVD) method usingvolatile organometallic compounds as precursors is widely used in thedeposition of metal oxide thin films, which are applied as highdielectric thin films, super-conductive thin films, electrodes, and thelike. Depending on the vaporization of precursor materials, the MOCVDmethod is generally classified into a bubbler method and a vaporizermethod. In the bubbler method, solid or liquid precursor materials arebubbled with a delivery gas to be sublimed. In the vaporizer method,precursor materials dissolved in suitable solvents are dropped onto ahot plate heated to a high temperature, so that the precursors arevaporized together with the solvents, thereby inducing efficientvaporization of the precursors. Since the vaporizer method adopts thedelivery of the precursors in liquid phase, it is also known as theliquid delivery method.

[0007] In order to form thin films on substrates by chemical vapordeposition, it is first necessary to provide precursors having excellentproperties. Also, good surface morphology, metal content and stepcoverage of the thin films formed using the precursors are necessary fortheir potential application as devices.

[0008] Properties of the precursors necessary for use in chemical vapordeposition include high volatility, distinct difference betweenvaporization temperature and decomposition temperature, low toxicity,chemical stability, thermal stability, easiness of synthesis and thermaldecomposition. In addition, during the vaporization or delivery of theprecursors, they must not be spontaneously decomposed or subjected to aside reaction with other precursors.

[0009] Particularly, for the formation of multi-component thin filmshaving a high quality, metal components deposited from metal precursorson a substrate must be easily controlled in their composition, and alsothe metal precursors must show similar behaviors in their decompositionat the deposition temperature.

[0010] Up to now, a variety of organometallic compounds, such as metalalkyls, metal alkoxides, metal carboxylates, and metal beta-diketonateshave been reported as precursors. However, these compounds did notsufficiently meet the property requirements, such as volatility,chemical and thermal stabilities, and toxicity, etc.

[0011] There were recently reported precursors of the formula M(OR)_(n)and precursors of the formula M(OR)_(x)(β-diketonate)_(y) in which themetal alkoxide is partially substituted with a bidentate ligand, such asβ-diketonate. However, such precursors still have problems in that theyare susceptible to moisture due to the alkoxide ligand present in themetal complex.

[0012] When intermolecular repulsive force of precursors is increasedwith fluorinated alkyls substituted with fluorine atoms of highelectronegativity for hydrogen atoms, volatility of the precursors isgenerally increased. To improve volatility of metal ions having a smallcharge-to-radius ratio, such as barium, strontium and the like, thereare commonly used methods that introduce a bulky alkyl group-containingligand or a polydentate Lewis base to saturate unsaturated coordinationsites of the metal ions. This saturation inhibits the oligomerizationand hydration of the complexes, and reduces the intermolecularinteraction. However, such methods result in new problems in that grownthin films may contain fluorine, and that the Lewis base is dissociatedduring vaporization or delivery of the precursors.

[0013] U.S. Pat. No. 4,950,790 assigned to Air Products and Chemicals,Inc. discloses metal β-ketoiminate compounds of the formula M^(n+)(β-ketoiminate)_(n) which have been improved in thermal and chemicalstabilities by filling vacant coordination sites of the metal withβ-ketoiminate as a bidentate ligand as a result of the chelate effectthereof. However, such compounds are problematic in that they are low inhydrolytic stability.

[0014] There were also reported precursors with a tridentateN-alkoxy-β-ketoiminate ligand having a charge of −2, such asTa(N-alkoxy-β-ketoiminate)(OEt₃) and Nb(N-alkoxy-β-ketoiminate)(OEt₃).However, since these precursors contain a highly reactive alkoxide groupin addition to the N-alkoxy-β-ketoiminate group as a ligand, they do notcontain advantages over the case where only N-alkoxy-β-ketoiminate isused as a ligand.

[0015] Furthermore, in depositing a multi-component metal oxide thinfilm such as barium strontium titanate (BST) thin film by the MOCVDmethod, there have been used titanium precursors in an excess amountover barium and strontium ones due to the large difference in volatilitybetween the metal precursors, thereby controlling the metal compositionof the thin film. However, titanium used in an excess amount causes arough surface of the thin film by forming titanium-based protrusions onthe surface of the thin film (see, Japanese Journal of Applied Physics,36, 6946 (1997)). Additionally, to apply the BST thin film tosemiconductor devices such as DRAMS, the thin film must contain littleor no impurities such as carbon. Also, to form a device structure, thethin film must be excellent in step coverage. However, multi-componentmetal oxide thin films deposited from the prior precursors aredisadvantageous in that they are rough in their surface due to the useof an excess amount of the titanium precursor, they are high in theirleakage current due to the presence of impurities such as carbon, etc.,and they are inferior in their step coverage.

SUMMARY OF THE INVENTION

[0016] A feature of the present invention is a group IV metal precursorwhich exhibits excellent volatility, thermal stability and Chemicalstability, and which is particularly suitable for use in the formationof multi-component metal oxide thin films containing a group IV metalsuch as titanium.

[0017] Another feature of the present invention is a chemical vapordeposition method using the group IV metal precursor.

[0018] In accordance with one aspect of the present invention, there isprovided a tridentate ligand (L) having a charge of −2, which isrepresented by the following formula (I):

[0019] wherein each of R₁ and R₂, independently, is a linear or branchedC₁₋₈ alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group.

[0020] In accordance with another aspect of the present invention, thereis provided an organometallic precursor of the formula M(L)₂, for use inthe formation of metal oxide thin films, in which M is a group IV metalion having a charge of +4 and L is a tridentate ligand of the aboveformula (I) having a charge of −2.

[0021] In accordance with still another aspect of the present invention,there is provided a chemical vapor deposition method which comprisesforming a metal oxide thin film using, as a group IV metal precursor,the organometallic precursor of the formula M(L)₂.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other objects and aspects of the present inventionwill be apparent from the following description of embodiments withreference to the accompanying drawings, in which:

[0023]FIG. 1a is a plot of Thermal Gravimetry-Differential ScanningCalorimetry (TG-DSC) curves according to a temperature rise in nitrogenatmosphere for the precursor titanium bis[4-(ethoxy)imino-2-pentanoate](Ti(eiP)₂) of the present invention;

[0024]FIG. 1b is a plot of TG-DSC curves according to a temperature risein nitrogen atmosphere for the precursor titaniumbis[4-(2-methylethoxy)imino-2-pentanoate] (Ti(2meip)₂) of the presentinvention;

[0025]FIG. 2a is a plot of TG-DSC curves according to a temperature riseunder a reduced pressure of about 1.3 mbar for the precursor Ti(eip)₂ ofthe present invention;

[0026]FIG. 2b is a plot of TG-DSC curves according to a temperature riseunder a reduced pressure of about 1.3 mbar for the precursor Ti(2meip)₂of the present invention;

[0027]FIG. 3 is a plot of TG-DSC curves according to a temperature risein air for the precursor Ti(2meip)₂ of the present invention;

[0028]FIG. 4 is a plot of graphs showing vaporization rates according totemperature that are measured in thermogravimetric analysis for theprecursor Ti(2meip)₂ Of the present invention and the commerciallyavailable precursors including titanium(2-methyl-2,4-dioxy-pentane)-bis(2,2,6,6-tetramethyl-3,5-heptanedionate)(Ti(mpd)(thd)₂),titanium bis(iso-propoxide)bis(2,2,6,6-tetramethyl-3,5-heptanedionate)(Ti(thd)₂ (O-iPr)₂), bariumbis(1-methoxyethoxy-2,2,6,6,-tetramethyl-3,5-hetanedionate)(Ba(methd)₂), and strontiumbis(1-methoxyethoxy-2,2,6,6,-tetramethyl-3,5-hetanedionate)(Sr(methd)₂);

[0029]FIG. 5a is a plot of graphs showing a variation in titanium andbarium contents according to deposition temperature in depositing abarium strontium titanate (BST) thin film using the precursor Ti(2meip)₂of the present invention;

[0030]FIG. 5b is a plot of graphs showing a variation in titanium andbarium contents according to deposition temperature in depositing abarium strontium titanate (BST) thin film using the prior precursorTi(mpd)(thd)₂;

[0031]FIG. 6 is a X-Ray Diffraction (XRD) pattern for a BST thin filmdeposited at 430° C. according to Example 24;

[0032]FIG. 7a is a image taken by a scanning electron microscope for aplane of a BST thin film deposited on a planar substrate at 430° C.according to Example 24;

[0033]FIG. 7b is a surface image taken by an atomic force microscope(AFM) for a plane of a BST thin film deposited on a planar substrate at430° C. according to Example 24;

[0034]FIG. 8 is a cross sectional image taken by a scanning electronmicroscope for a BST thin film deposited on a fine-patterned substrateat 430° C. according to Example 24;

[0035]FIG. 9 is a plot that shows analytical results by the SecondaryIon Mass Spectroscopy of a BST thin film deposited at 430° C. accordingto Example 24;

[0036]FIG. 10 is a plot that shows the dielectric characteristics of aPt/BST/Pt capacitor, which has a BST thin film deposited at 430° C.according to Example 24; and

[0037]FIG. 11 is a plot that shows leakage current density of aPt/BST/Pt capacitor, which has a BST thin film deposited at 430° C.according to Example 24.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The present invention provides a chemical vapor deposition methodusing, as a titanium precursor, titanium (N-alkoxy-β-ketoiminate)₂ whichwas previously reported as a catalyst in “Organometallics, 18, 1018(1999)”. Such a titanium precursor is saturated at the vacantcoordination sites of the central titanium ion with two tridentateligands which show much enhanced chelate effect over a bidentate ligand.Thus, this precursor is excellent in chemical stability and thermalproperties, and does not leave residue after vaporization. Also, thisprecursor can be controlled with respect to its thermal properties, suchas vaporization temperature, and residue amount after vaporization, etc.This allows the insurance of a similarity in vaporization anddecomposition behaviors among metal precursors that are used in thedeposition of a multi-component metal oxide thin film containingtitanium. The ligand N-alkoxy-β-ketoiminate can be also applied to othergroup IV metal ions including Si, Zr, Hf, Ge, Sn and Pb in addition toTi.

[0039] Briefly, the method of the present invention utilizes, as a groupIV metal precursor, a complex represented by the formula M(L)₂ where Mis a group IV metal ion and L is the ligand. The ligand (L) ischaracterized in that it is N-alkoxy-β-ketoiminate having a charge of −2as indicated in the formula (I) below and is coordinated to a group IVmetal ion having a charge of +4 as a tridentate ligand:

[0040] wherein each of R₁ and R₂, independently, is a linear or branchedC₁₋₈ alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group. Inparticular, the R₁ and R₂ groups may be the same or different from oneanother to render the ligand (L) asymmetric.

[0041] To further improve the chelate effect of the ligand, the presentinvention introduces a linear or branched N-alkoxy group having a chargeof −1 to a nitrogen atom of β-ketoiminate to convert the β-ketoiminateinto a tridentate ligand having a charge of −2. The tridentate ligandthus prepared is strongly bound to a metal ion while saturating vacantcoordination sites of the metal ion. Accordingly, the metal complex withthe ligand (L) achieves excellent chemical and thermal stabilities.

[0042] Meanwhile, precursors of a formula M(OR)_(n) and precursors of aformula M(OR)_(x)(β-diketonate)y are generally converted into metalhydroxide complexes when being left to stand in air. In contrast, theprecursors having the tridentate ligand according to the presentinvention, in particular the precursor Ti(2meip)₂ according to thefollowing Example 12, have an excellent hydrolytic stability, as well asan excellent chemical stability in that they are not structurallychanged even when left to stand in air for three months or more.

[0043] Since the group IV metal precursors according to the presentinvention are soluble in common organic solvents, such as benzene,toluene, chloroform, alcohol, tetrahydrofuran and n-butyl acetate, theycan be used to form a thin film on a substrate by the Liquid DeliveryMOCVD method. In particular, such precursors have an advantage in thatits solubility in solvents such as n-butyl acetate commonly used in aLiquid Source Chemical Vapor Deposition (LSCVD) method may be increasedby varying asymmetric moieties of the tridentate ligand.

[0044] The precursors according to the present invention exhibit highlyimproved thermal stability, are moisture proof and exhibit chemicalstability. These properties are significantly dependent on the asymmetryof the ligand, as well as the kinds of groups R₁, R₂ and R₃. In the caseof the precursor Ti(epi)₂ where the tridentate ligand does not containany asymmetric moiety, it leaves a residue of about 8% afterevaporation. In contrast, the precursors Ti(2meip)₂ and Ti(22dm2meih)₂(titanium bis[2,2-dimethyl-5-(2-methylethoxy) imino-3-heptanonate]),respectively, are melted at 198° C. and 218° C. under atmosphericpressure and then rapidly vaporized at 290° C. and 287° C. without beingthermally decomposed. It can be thus found that the precursorsTi(2meip)₂ and Ti(22dm2meih)₂ possess excellent thermal properties inthat they leave no residues after being vaporized.

[0045] In depositing a multi-component thin film by the chemical vapordeposition (CVD) method, metal precursors used are generally differentin their vaporization temperature from each other and are not similar intheir decomposition behavior. For this reason, supplying excess metalprecursor of a relatively high volatility is necessary to control themetal composition of the thin film. Accordingly, in the deposition ofmulti-component thin film, the use of a combination of precursors havingsimilar volatility and decomposition behaviors is highly critical toform a thin film having a good quality. In particular, precursors havinga small charge-to-radius ratio, such as Ba, Sr and the like, are notsufficiently coordinated with ligands at their coordination sites. Thus,the precursors having such metals are higher in vaporization temperatureby at least 100° C. compared to the titanium precursor, as indicated inTable 2. However, while the precursors according to the presentinvention are vaporized at a higher temperature than that of the priortitanium precursors, they leave no residues after vaporization and arecompletely decomposed above a certain temperature on thermaldecomposition in an oxygen atmosphere. Thus, the precursors according tothe present invention are particularly useful in forming amulti-component thin film with metals of a low volatility. In addition,the precursors of the present invention enable the formation of a highquality-thin film which has a smooth surface and excellent stepcoverage, and which contains little or no impurities, such as carbon ornitrogen, etc.

[0046] Meanwhile, in depositing the multi-component thin film such asBST on a large area substrate, the temperature of the substrate is notmaintained uniformly throughout the substrate. Moreover, in fabricatinga device with a high aspect ratio, the higher and lower topologyportions of the device are not maintained at the same temperature. Forthese reasons, it was difficult for the prior methods to maintain thetitanium content at the same level throughout the large area substrateor the upper and lower portions of the high topology thin film. Incontrast, for the titanium precursor according to the present invention,the temperature dependence of the titanium content in thin film is lowas compared to that for the prior titanium precursors. This provideseasy control of the metal composition in the large area thin film andthe high topology thin film.

[0047] The following examples are for further illustration purposes onlyand in no way limit the scope of this invention.

Example 1 Preparation of CH₃C (O)CHC(HNCH₂CH₂OH)CH₃

[0048] As described in Organometallics, 18, 1018 (1999), 6.71 g (109.8mmol) of ethanol amine of a formula NH₂CH₂CH₂OH and 10 g (99.88 mmol) of2,4-pentanedione of a formula CH₃C(O)CH₂C(O)CH₃, as starting materials,were mixed with 120 ml of CH₂Cl₂, and stirred for one day at roomtemperature. Then, the resulting material was extracted with a mixedsolution of H₂O/CH₂Cl₂ (15 ml/150 ml) into an organic layer, and theremaining water layer was further extracted three times with 100 ml of aCH₂Cl₂ solution. After drying the collected organic solution in thepresence of MgSO₄, the solvent was removed from the solution, andCH₂Cl₂/n-hexane (10 ml/140 ml) was added. As a result, the mixture wasrecrystallized at −20° C. to give 12.88 g (90% yield) ofCH₃C(O)CHC(HNCH₂CH₂OH)CH₃.

Example 2 Preparation of CH₃C(O)CHC(HNCH₂CH(CH₃)OH)CH₃

[0049] The same procedure as in Example 1 was carried out to give 29.38g (95% yield) of CH₃C(O)CHC(HNCH₂CH(CH₃)OH)CH₃, except that 22.51 g(299.7 mmol) of 1-amino-2-propanol of a formula NH₂CH₂CH(CH₃)OH and 20 g(199.8 mmol) of 2,4-pentanedion were used as the starting materials.

Example 3 Preparation of CH₃C(O)CHC(HNCH (CH₃)CH₂OH)CH₃

[0050] 10.0 g (13.31 mmol) of DL-2-amino-1-propanol of a formulaNH₂CH(CH₃)CHOH and 11.11 g (11.10 mmol) of 2,4-pentanedione were mixedwith 100 ml of CH₃OH, to which 0.51 g of HCOOH was added. The mixturewas refluxed for one day at 85° C. while stirring. After removing thesolvent, the resulting material was extracted with a mixed solution ofH₂O/CH₂Cl₂ (20 ml/150 ml) into an organic layer, and the remaining waterlayer was further extracted three times with 100 ml of a CH₂Cl₂solution. After drying the collected organic solution in the presence OfMgSO₄, the solvent was removed from the solution. The remaining materialwas purified through a column filled with silica, using ethyl acetate asa developing solution, to give 15.52 g (89% yield) of CH₃C(O)CHC(HNCH(CH₃)CH₂OH)CH₃.

[0051] NMR results measured for the product are as follows:

[0052]¹H-NMR (199.976 MHz, CDCl₃): 10.8(br s, 1H, C(O)CH═C(NH)) 4.93(s,1H, C(O)CH═C(NH)), 3.72(m, 1H, HNCH(Me)CH₂OH), 3.62(dd, 1H,NCHMeCH_(a)H_(b)OH), 3.52(dd, 1H, NCHMeCH_(a)H_(b)OH), 3.35(br s, 1H,NCH(Me)CH₂OH), 1.98(s, 3H, CH═C(NH)CH₃), 1.97(s, 3H, CH₃C(O)CH), 1.18(d,3H, HNCH(CH₃)CH₂OH); ¹³C-NMR (50.289 MHz, CDCl₃): 192.45(s, CH₃C(O)CH),160.69(s, CH═C(NH)CH₃), 93.19(s, C(O)CH═C(NH), 64.57(s, HNCH(Me)CH₂OH),48.45(s, HNCH(Me)CH₂OH), 26.19(s, CH₃C(O)CH), 16.69(s, CH═C(NH)CH₃),15.7(s, NHCH(CH₃)CH₂OH)

Example 4 Preparation of CH₃C(O)CHC(HNC(CH₃)₂CH₂OH)CH₃

[0053] 13.35 g (149.8 mmol) of 2-amino-2-methyl-1-propanol of a formulaNH₂C(CH₃)₂CHOH and 10.0 g (99.88 mmol) of 2,4-pentanedione, as startingmaterials, were mixed with 100 ml of CH₃OH, to which 0.51 g of HCOOH wasadded. The mixture was refluxed for one day at 85° C. while stirring.After removing the solvent, the remaining material was recrystallizedfrom ethyl ether at room temperature to give 10.95 g (64% yield) ofCH₃C(O)CHC(HNC(CH₃)₂CH₂OH)CH₃.

[0054] NMR results measured for the product are as follows:

[0055]¹H-NMR (199.976 MHz, CDCl₃): 11.32(br s, 1H, C(O)CH═C(NH)),4.88(s, 1H, C(O)CH═C(NH)), 4.35(br s, 1H, HNC(Me)₂CH₂OH), 3.53(s, 2H,NC(Me)₂CH₂OH), 2.04(s, 3H, CH═C(N)CH₃), 1.94(s, 3H, CH₃C(O)), 1.33(s,6H, (HNC(CH₃)₂CH₂OH); ¹³C-NMR (50.289 MHz, CDCl₃): 194.24(s, CH₃C(O)CH),163.88(s, CH═C(NH)CH₃), 97.07(s, C(O)CH═(NH)), 70.93(s, NHC(Me)₂CH₂OH),56.44(s, HNC(Me)₂CH₂OH), 28.67(s, CH═C(NH)CH₃), 25.72(s,HNC(CH₃)₂CH₂OH), 20.96(s, CH₃C(O)CH); EA (cal C: 63.13, H: 10.01, N:8.18, found C: 63.38, H: 10.57, N: 8.23)

Example 5 Preparation of CH₃C(O)CHC(HNCH(CH₂CH₃)CH₂OH)CH₃

[0056] The same procedure as in Example 3 was carried out, except that13.35 g (149.8 mmol) of 2-amino-1-butanol and 10.0 g (99.88 mmol) of2,4-pentanedion, as the starting materials, were mixed with 100 ml ofC₂H₅OH. The product was finally purified through vacuum distillation togive 14.54 g (85% yield) of CH₃C(O)CHC(HNCH(CH₂CH₃)CH₂OH)CH₃ as ayellowish liquid.

[0057] NMR results measured for the product are as follows:

[0058]¹H-NMR (199.976 MHz, CDCl₃): 10.74(br s, 1H, C(O)CH═C(NH)),4.94(s, 1H, C(O)CH═C(NH)), 4.06(d, 2H, NCH(CH₂CH₃)CH₂OH), 3.60(m, 1H,NCH(CH₂CH₃)CH₂OH), 3.25(br s, 1H, HNCH(CH₂CH₃)CH₂OH), 1.99(s, 3H,CH═C(N)CH₃), 1.93(s, 3H, CH₃C(O)), 1.59(m, 2H, (HNCH(CH₂CH₃)CH₂OH),0.95(t, 3H, HNCH(CH₂CH₃)CH₂OH); ¹³C-NMR (50.289 MHz, CDCl₃): 195.15(s,CH₃C(O)CH), 163.86(s, CH═C(NH)CH₃), 95.87(s, C(O)CH═C(NH)), 65.91(s,HNCH(CH₂CH₃)CH₂OH), 57.23(s, HNCH(CH₂CH₃)CH₂OH), 28.90(s, CH₃C(O)CH),25.54(s, HNCH(CH₂CH₃)CH₂OH), 19.66(s, CH═C(NH)CH₃), 10.56(s,NHCH(CH₂CH₃)CH₂OH).

Example 6 Preparation of CH₃C(O)CHC(HNCH₂CH₂CH₂OH)CH₃

[0059] The same procedure as in Example 1 was carried out, except that9.0 g (119.8 mmol) of 3-amino-1-propanol and 10.0 g (99.88 mmol) of2,4-pentanedion were used as the starting materials. The product wasfinally purified through a column filled with silica, using a mixedsolution of ethyl acetate/hexane as a developing solution, to give 14.00g (93% yield) of CH₃C(O)CHC(HNCH₂CH₂CH₂OH)CH₃.

[0060] NMR results measured for the product are as follows:

[0061]¹H-NMR (199.976 MHz, CDCl₃): 10.86(br s, 1H, C(O)CH═C(NH)),4.96(s, 1H, C(O)CH═C(NH)), 3.74(t, 2H, NCH₂CH₂CH₂OH), 3.38(dt, 2H,NCH₂CH₂CH₂OH), 2.67(br s, 1H, NCH₂CH₂CH₂OH), 1.98(s, 3H, CH═C(NH)CH₃),1.94(s, 3H, CH₃C(O)CH), 1.83(m, 2H, NCH₂CH₂CH₂OH); ¹³C-NMR (50.289 MHz,CDCl₃): 194.94 (s, CH₃C(O)CH), 163.80 (s, CH═C(NH)CH₃), 95.46(s,C(O)CH═C(NH)), 59.62(s, HNCH₂CH₂CH₂OH), 39.92(s, HNCH₂CH₂CH₂OH),32.85(s, HNCH₂CH₂CH₂OH), 28.85(s, CH₃C(O)CH), 18.99 (s, CH═C(NH)CH₃).

Example 7 Preparation of (CH₃)₂CHC(O)CHC(HNCH₂CH(CH₃)OH)(CH(CH₃)₂)

[0062] 5.77 g (76.8 mmol) of 1-amino-2-propanol of a formulaNH₂CH₂CH(CH₃)OH and 10.0 g (64.0 mmol) of 2,6-dimethyl-3,5-heptanedioneof a formula (CH₃)₂CHC(O)CH₂C(O)(CH(CH₃)₂) were mixed with 180 ml of abenzene solution, to which 0.63 g (1 drop) of H₂SO₄ or HCOOH was added.The mixture was refluxed for 6 hours at 110° C. with stirring, and H₂Owas collected through a Dean-Stark device. The remaining material wasextracted with a mixed solution of H₂O/benzene (20 ml/250 ml) into anorganic layer, and the remaining water layer was further extracted threetimes with 100 ml of a benzene solution. After drying the collectedorganic solution in the presence of MgSO₄, the solvent was removed fromthe solution, and 100 ml of n-hexane was added. The mixture wasrecrystallized at −20° C. to give 11.61 g (85% yield) of(CH₃)₂CHC(O)CHC(HNCH₂CH(CH₃) OH)(CH(CH₃)₂)

[0063] NMR results measured for the product are as follows:

[0064]¹H NMR (CDCl₃): 11.21 (br s, 1H, C(O)CH═CNH), 5.01 (s, 1H,C(O)CH═CNH), 3.95 (q, 1H, HNCH₂CHMeOH), 3.42 (br s, 1H, NCH₂CH₂OH), 3.22(m, 2H, HNCH₂CHMeOH), 2.70 (h, 1H, HNCCHMe₂), 2.42 (h, 1H, Me₂CHC(O)CH),1.23 (d, 3H, NCH₂CH(CH₃)OH), 1.10 (d, 6H, HNCCH(CH₃)₂), 1.05 (d, 6H,(CH₃)₂CHC(O)CH); ¹³C NMR (CDCl₃): 200.82 (s, Me₂CHC(O)CH), 171.90 (s,HNCCHMe₂), 86.42 (s, C(O)CH═CN), 65.13 (s, NCH₂CHMeOH), 47.92 (s,HNCH₂CHMeOH), 38.12 (s, Me₂CHC(O)CH), 26.85 (s, HNCCHMe₂), 19.56 (s,HNCCH(C_(a)H₃)(C_(b)H₃)), 19.47 (s, HNCCH(C_(a)H₃)(C_(b)H₃)), 19.20 (s,NCH₂CH(CH₃)OH), 18.27 (s, (CH₃)₂CHC(O)CH), EA(cal C: 67.57 , H: 10.87,N: 6.56 , Found C: 67.44, H: 11.33, N: 6.48).

Example 8 Preparation of (CH₃)₂CHC(O)CHC(HNCH(CH₃)CH₂OH)(CH(CH₃)₂)

[0065] The same procedure as in Example 7 was carried out to give 11.659 (81% yield) of (CH₃)₂CHC(O)CHC(HNCH(CH₃)CH₂OH)(CH(CH₃)₂), except that7.21 g (95.99 mmol) of DL-2-amino-1-propanol and 10.0 g (64.0 mmol) of2,6-dimethyl-3,5-heptanedion were used as the starting materials.

[0066] NMR results measured for the product are as follows:

[0067]¹H-NMR (199.976 MHz, CDCl₃): 11.12(br d, 1H, C(O)CH═C(NHCH(Me))),5.03(s, 1H, C(O)CH═C(NH)), 3.79(m, 1H, HNCH(Me)CH₂OH), 3.59(br m, 2H,NCHMeCH₂OH), 2.89(br s, 1H, NCH(Me)CH₂OH), 2.78(m, 1H,CH═C(NH)CH(CH₃)₂), 2.45(m, 1H, (CH₃)₂CHC(O)CH), 1.22(d, 3H,NCH(CH₃)CH₂OH), 1.15(d, 6H, CH═C(N)CH(CH₃)₂), 1.07 (dd, 6H(CH₃)₂CHC(O)); ¹³C NMR (CDCl₃): 202.57 (s, Me₂CHC(O)CH), 173.73 (s,HNCCHMe₂), 88.24 (s, C(O)CH═CN), 67.28 (s, NCH(Me)CH₂OH), 50.00 (s,HNCH(Me)CH₂OH), 39.93 (s, Me₂CHC(O)CH), 28.75 (s, HNCCHMe₂), 22.03 (s,HNCCH(C_(a)H₃)(C_(b)H₃)), 21.72 (s, HNCCH(C_(a)H₃)(C_(b)H₃)), 20.16 (s,(CH₃)₂CHC(O)CH) 18.90 (s, NCH(CH₃)CH₂OH); EA(cal C: 67.57, H: 10.87, N:6.57. Found C: 67.44, H: 11.70, N: 6.52).

Example 9 Preparation of (CH₃)₃CC(O)CHC(HNCH₂CH₂OH)CH₃

[0068] The same procedure as in Example 7 was carried out to give 9.40 g(89% yield) of (CH₃)₃CC(O)CHC(HNCH₂CH₂OH)CH₃, except that 9.73 9 (68.44mmol) of ethanol amine and 8.11 g (57.03 mmol) of2,2-dimethyl-3,5-hexanedion were used as the starting materials.

[0069] NMR results measured for the product are as follows:

[0070]¹H NMR (CDCl₃): 11.04 (br s, 1H, C(O)CH═CNH), 5.14 (s, 1H,C(O)CH═CNH), 3.76 (t, 2H, HNCH₂CH₂OH), 3.39 (dt, 1H, HNCH₂CH₂OH), 3.11(br s, 1H, HNCH₂CH₂OH), 1.97 (s, 3H, HNCCH₃), 1.11(s, 9H,(CH₃)₃CC(O)CH); ¹³C NMR (CDCl₃): 202.39 (s, Me₃CC(O)CH), 162.54 (s,HNCCH₃), 89.32 (s, C(O)CH═CNH), 60.02 (s, NCH₂CH₂OH), 43.63 (s,HNCH₂CH₂OH), 39.58 (s, (CH₃)₃CC(O)CH), 26.25 (s, (CH₃)₃CC(O)CH), 17.82(s, HNCCH₃); EA(cal C: 64.83, H: 10.34, N: 7.56. Found C: 64.76, H:10.82, N: 7.60).

Example 10 Preparation of (CH₃)₃CC(O)CHC(HNCH₂CH(CH₃)OH)CH₃

[0071] The same procedure as in Example 3 was carried out, except that6.34 g (84.38 mmol) of 1-amino-2-propanol and 10.00 g (70.32 mmol) of2,2-dimethyl-3,5-hexanedion, as the starting materials, were mixed withC₂H₅OH. The product was recrystallized from n-hexane at −20° C. to give10.93 g (78% yield) of (CH₃)₃CC(O)CHC(HNCH₂CH(CH₃)OH)CH₃.

[0072] NMR results measured for the product are as follows:

[0073]¹H NMR (CDCl₃): 11.04 (br s, 1H, C(O)CH═CNH), 5.13 (s, 1H,C(O)CH═CNH), 3.96 (m, 1H, HNCH₂CH(Me)OH), 3.26 (dd, 1H,HNCH_(a)H_(b)CH(Me)OH), 3.20 (dd, 1H, HNCH_(a)H_(b)CH(Me)OH), 3.19 (brs, 1H, HNCH₂CH(Me)OH), 1.96 (s, 3H, HNCCH₃), 1.23(d, 3H,HNCH₂CH(CH₃)OH), 1.11(s, 9H, (CH₃)₃CC(O)CH); ¹³C NMR (CDCl₃): 204.16 (s,Me₃CC(O)CH), 164.20 (s, HNCCH₃), 91.18 (s, C(O)CH═CNH), 67.11 (s,NCH₂CH(Me)OH), 50.71 (s, HNCH₂CH(Me)OH), 41.46(s, (CH₃)₃CC(O)CH),28.16(s, (CH₃)₃CC(O)CH), 21.00 (s, HNCCH₃), 19.77 (s, HNCH₂CH(CH₃)OH);EA (cal C: 66.29, H: 10.62, N: 7.03 , found C: 65.72, H: 11.08, N:7.12).

Example 11 Preparation of Ti(CH₃C(O)CHC(NCH₂CH₂O)CH₃)₂, Ti(eip)₂

[0074]3.67 g (25.61 mmol) of the tridentate ligand of a formulaCH₃C(O)CHC(CH₃)(HNCH₂CH₂OH) prepared in Example 1 was dissolved in 20 mlof methylene dichloride. To this solution, a solution of 3.31 g (11.64mmol) of titanium(isopropoxide)₄, Ti(O-iPr)₄, in 25 ml of methylenedichloride was added through a cannular at room temperature withstirring. The mixed yellowish solution was stirred for 4 hours or more,after which the solvent was removed under a reduced pressure. Theremaining material was recrystallized from a mixed solution of methylenedichloride and n-hexane at −20° C. to give 3.72 g (95% yield) ofTi(CH₃C(O)CHC(NCH₂CH₂O)CH₃)₂ as a pure yellow solid.

Example 12 Preparation of Ti(CH₃C(O)CHC(NCH₂CHMeO)CH₃)₂, Ti(2meip)₂

[0075] This Example was carried out according to the same procedure asin Example 11, using 11.06 g (70.36 mmol) ofCH₃C(O)CHC(CH₃)(HNCH₂CH(Me)OH) prepared in Example 2 and 10.0 g (35.18mmol) of Ti(O-iPr)₄. Thus, 12.18 g (96% yield) ofTi(CH₃C(O)CHC(NCH₂CHMeO)CH₃)₂ was obtained.

Example 13 Preparation of Ti(CH₃C(O)CHC(NCHMeCH₂O)CH₃)₂, Ti(1meip)₂

[0076] This Example was carried out according to the same procedure asin Example 11, using 8.0 g (50.89 mmol) of CH₃C(O)CH₂C(CH₃)(NCHMeCH₂OH)prepared in Example 3 and 7.23 g (25.44 mmol) of Ti(O-iPr)₄. Thus, 8.38g (92% yield) of Ti(CH₃C(O)CHC(NCHMeCH₂O)CH₃)₂ was obtained.

[0077] NMR results measured for the product are as follows:

[0078]¹H-NMR (199.976 MHz, CDCl₃) 5.27, 5.24, 5.08, 5.08 (s 2H,C(O)CHC(N)), 4.79 (dd , 1H, NCH(Me)CH_(ab)H_(cd)O), 4.58(dd 1H,NCH(Me)CH_(ab)H_(cd)O), 4.35 (m, 2H, NCH(Me)CH₂O), 4.00(dd , 1H,NCH(Me)CH_(ab)H_(cd)O), 3.83(dd , 1H, NCH(Me)CH_(ab)H_(cd)O), 2.14,2.12, 2.11, 2.07(s , 6H, C(N)CH₃), 1.94, 1.92, 1.88, 1.80(s, 6H,CH₃C(O)), 1.51, 1.37, 1.32, 1.24, 1.17(d , 6H, NCH(CH₃)CH₂O); ¹³C-NMR(50.289 MHz, CDCl₃) 176.72, 175.83, 175.40(s, CH₃C(O)), 167.89, 167.27,166.76(s, C(N)CH₃), 103.30, 103.20, 102.01(s, C(O)CHC(N)), 78.07, 78.00,77.14(s, NCH(Me)CH₂O), 66.14, 65.73, 65.24, 64.96(s, NCH(Me)CH₂O),24.92, 24.58, 24.40, 24.25(CH₃C(O)), 21.82, 21.59, 21.43,20.74(C(N)CH3), 20.35, 20.08, 19.30, 18.35(NCH(CH₃)CH₂O); EA (cal C:53.64, H: 7.32, N: 7.82 , found C: 53.32, H: 7.66, N: 7.79)

Example 14 Preparation of Ti(CH₃C(O)CHC(NC(Me)₂CH₂O)CH₃)₂, Ti(1deip)₂

[0079] This Example was carried out according to the same procedure asin Example 11, using 3.01 g (17.58 mmol) ofCH₃C(O)CHC(CH₃)(HNC(Me)₂CH₂OH) prepared in Example 4 and 2.50 g (8.79mmol) of Ti(O-iPr)₄. Thus, 3.19 g (94% yield) ofTi(CH₃C(O)CHC(NC(Me)₂CH₂O)CH₃)₂ was obtained.

[0080] NMR results measured for the product are as follows:

[0081]¹H-NMR (199.976 MHz, CDCl₃) 5.13 (s, 2H, C(O)CHC(N)), 4.32 (d, 2H,NC(Me)₂CH_(a)H_(b)O), 4.01 (d, 2H, NC(Me)₂CH_(a)H_(b)O), 2.21(s, 6H,C(N)CH₃), 1.92 (s, 6H, CH₃C(O)), 1.56 (s, 6H, NC(CH₃)_(a)(CH₃)_(b)CH₂O),1.38 (s, 6H, NC(CH₃)_(a)(CH₃)_(b)CH₂O); ¹³C-NMR (50.289 MHz, CDCl₃)174.70(s, CH₃C(O)), 169.31(s, C(N)CH₃), 104.71(s, C(O)CHC(N)), 84.79(s,NC(Me)₂CH₂O), 71.41(s, NC(Me)₂CH₂O), 25.69(s, CH₃C(O)), 25.1(s,C(N)CH₃), 24.5(s, NCC_(a)H₃C_(b)H₃CH₂O), 24.4(s, NCC_(a)H₃C_(b)H₃CH₂O);EA (cal C: 55.96, H: 7.83, N: 7.25 , found C: 55.59, H: 8.22, N: 6.87).

Example 15 Preparation of Ti(CH₃C(O)CHC(NCH(CH₂CH₃)CH₂O)CH₃)₂,Ti(1eeip)₂

[0082] This Example was carried out according to the same procedure asin Example 11, using 2.30 g (13.44 mmol) ofCH₃C(O)CHC(HNCH(CH₂CH₃)CH₂O)CH₃ prepared in Example 5 and 1.91 g (6.72mmol) of Ti(O-iPr)₄. Thus, 2.41 g (93% yield) ofTi(CH₃C(O)CHC(NCH(CH₂CH₃)CH₂O)CH₃)₂ was obtained.

[0083] NMR results measured for the product are as follows:

[0084]¹H-NMR (199.976 MHz, CDCl₃) 5.28, 5.25, 5.09 (s , 2H, C(O)CHC(N)),4.70 (dd , 1H, NCH(CH₂CH₃)CH_(ab)H_(cd)O), 4.65(dd 1H,NCH(CH₂CH₃)CH_(ab)H_(cd)O), 4.18(dd , 1H, NCH(CH₂CH₃)CH_(ab)H_(cd)O),4.17(dd , 1H, NCH(CH₂CH₃)CH_(ab)H_(cd)O), 4.03 (m, 2H, NCH(CH₂CH₃)CH₂O),2.29-2.14(m , 2H, NCH(CH₂CH₃)CH₂O), 2.11, 2.06 (s , 6H, C(N)CH₃), 1.92,1.89, 1.80(s, 6H, CH₃C(O)), 1.72-1.55(m, 2H, NCH(CH₂CH₃)CH₂O), 0.97(t ,6H, NCH(CH₂CH₃)CH₂O); ¹³C-NMR (50.289 MHz, CDCl₃) 175.89, (s, CH₃C(O)),167.13(s, C(N)CH₃), 102.04(s, C(O)CHC(N)), 74.46(s, NCH(CH₂CH₃)CH₂O)72.78(s, NCH(CH₂CH₃)CH₂O), 24.48(s, NCH(CH₂CH₃)CH₂O), 24.67(CH₃C(O)),21.99(C(N)CH₃), 11.77(NCH(CH₂CH₃)CH₂O); EA (cal C: 55.96, H: 7.83, N:7.25 found C: 55.85, H: 8.30, N: 7.34).

Example 16 Preparation of Ti(CH₃C(O)CHC(NCH₂CH₂CH₂O) CH₃)₂, Ti(pip)₂

[0085] This Example was carried out according to the same procedure asin Example 11, using 1.11 g (7.04 mmol) of CH₃C(O)CHC(HNCH₂CH₂CH₂O)CH₃prepared in Example 6 and 1.0 g (3.52 mmol) of Ti(O-iPr)₄. Thus, 1.20 g(95.24% yield) of Ti(CH₃C(O)CHC(NC(Me)₂CH₂O)CH₃)₂ was obtained.

[0086] NMR results measured for the product are as follows:

[0087]¹H-NMR (199.976 MHz, CDCl₃) 5.14(s, 2H, C(O)CHC(N)), 4.36(t, 4H,NCH₂CH₂CH₂O), 3.64(t, 4H, NCH₂CH₂CH₂O), 2.07(m, 4H, NCH₂CH₂CH₂O),2.00(s, 6H, C(N)CH₃), 1.90(s, 6H, CH₃C(O); ¹³C-NMR (50.289 MHz, CDCl₃)176.05(s, CH₃C(O)), 168.01(s, C(N)CH₃), 103.64(s, C(O)CHC(N)), 73.23(s,NCH₂CH₂CH₂O), 50.19(s, NCH₂CH₂CH₂O), 32.34(s, NCH₂CH₂CH₂O), 25.33(s,CH₃C(O)), 22.41(s, C(N)CH₃).

Example 17 Preparation of Ti((CH₃)₂CHC(O)CHC(CH(CH₃)₂)(NCH₂CH(Me)C)₂)₂,Ti(26dm2meih)₂

[0088] This Example was carried out according to the same procedure asin Example 11, using 1.5 g (7.03 mmol) of(CH₃)₂CHC(O)CHC(CH(CH₃)₂)(HNCH₂CH(Me)OH) prepared in Example 7 and 1.0 g(3.52 mmol) of Ti(O-iPr)₄. Thus, 1.57 g (95% yield) ofTi((CH₃)₂CHC(O)CHC(NCH₂CH(Me)O)CH(CH₃)₂)₂ was obtained.

[0089] NMR results measured for the product are as follows:

[0090]¹H-NMR (199.976 MHz, CDCl₃) 5.23, 5.22, 5.20, 5.15 (s, 2H,C(O)CHC(N)), 4.87(m, 2H, NCH₂CHMeO), 4.22(dd , 1H,NCH_(ab)H_(cd)CH(Me)O), 4.13(dd, 1H, NCH_(ab)H_(cd)CH(Me)O), 3.88(dd ,1H, NCH_(ab)H_(cd)CH(Me)O), 3.76(dd, 1H, NCH_(ab)H_(cd)CH(Me)O), 2.92(m,2H, C(N)CH(Me)₂), 2.30(m, 2H, CH(Me)₂C(O)), 1.11-1.23(d*4, 12H,C(N)CH(CH₃)₂), 1.21(d*3, 6H, NCH₂CH(CH₃)O), 0.88-0.98 (d*4, 12H,(CH₃)₂CHC(O)); ¹³C-NMR (50.289 MHz, CD₂Cl₂) 183.51, 183.35, 183.02(s,(CH₃)₂CHC(O)), 177.05, 176.49, 175.91, 175.70(s, C(N)(CH(CH₃)₂)), 93.46,93.30, 93.19(s, C(O)CHC(N)), 76.99, 76.52, 76.40, 76.12(s, NCH₂CH(Me)O),65.96, 65.60, 64.79(s, NCH₂CH(Me)O), 36.35, 36.27, 36.13(s,(CH₃)₂CHC(O)), 31.46, 31.40, 31.24(s, C(N)(CH(CH₃)₂)), 21.66-20.18 (d,(CH₃)₂CHC(O)CHC(NCH₂CH(CH₃)O)(CH(CH₃)₂))

Example 18 Preparation of Ti((CH₃)₂CHC(O)CHC(NCH(Me)CH₂O)CH(CH₃)₂)₂,Ti(26dm1meih)₂

[0091] This Example was carried out according to the same procedure asin Example 11, using 6.0 g (28.14 mmol) of(CH₃)₂CHC(O)CH₂C(CH(CH₃)₂)(NCH(Me)CH₂OH) prepared in Example 8 and 4.0 g(14.07 mmol) of Ti(O-iPr)₄. Thus, 6.22 g (93.96% yield) ofTi((CH₃)₂CHC(O)CHC(NCH(Me)CH₂O)CH(CH₃)₂)₂ was obtained.

[0092] NMR results measured for the product are as follows:

[0093]¹H-NMR (199.976 MHz, CDCl₃) 5.34, 5.17, 5.13(s , 2H, C(O)CHC(N)),4.83(dd , 1H, NCH(Me)CH_(ab)H_(cd)O), 4.79(dd , 1H,NCH(Me)CH_(ab)H_(cd)O), 4.56(m, 1H, NCH_(a)(Me)CH₂O), 4.38(m, 1H,NCH_(b)(Me)CH₂O), 4.03(dd , 1H, NCH(Me)CH_(ab)H_(cd)O), 3.95(dd , 1H,NCH(Me)CH_(ab)H_(cd)O), 3.03(m, 2H, C(N)(CH(CH₃)₂), 2.39(m, 1H,(CH₃)₂CH_(a)C(O)), 2.30(m, 1H, (CH₃)₂CH_(b)C(O)), 1.51, 1.41, 1.37(d,6H, NCH(CH₃)CH₂O), 1.24-1.13(d*4, 12H, C(N)(CH(CH₃)₂) 1.04-0.85(d*5,12H, (CH₃)₂CHC(O)); ¹³C-NMR (50.289 MHz, CDCl₃) 183.45, 182.98,182.81(s, CH₃C(O)), 175.95, 175.70, 175.32(s, C(N)CH₃), 94.31, 93.84,93.59(s, C(O)CHC(N)), 76.80, 76.69, 76.36(s, NCH(Me)CH₂O), 64.77, 64.36,63.59(s, NCH(Me)CH₂O), 36.46, 36.36, 36.22(s, (CH₃)₂CHC(O)), 31.20,31.00, 30.90(s, C(N)CH(CH₃)₂), 22.32, 22.17, 22.10, 22.05(s,NCH(CH₃)CH₂O), 21.87, 21.66, 21.60, 21.50(s, C(N)CH(CH₃)₂), 20.89,20.78, 20.63, 20.52(s, (CH₃)₂CHC(O)); EA (cal C: 61.27, H: 9.00, N: 5.95, found C: 61.33, H: 9.48, N: 5.72).

Example 19 Preparation of Ti((CH₃)₃CC(O)CHC(NCH₂CH₂O) CH₃)₂,Ti(22dmeih)₂

[0094] This Example was carried out according to the same procedure asin Example 11, using 4.98 g (26.88 mmol) of(CH₃)₃CC(O)CHCCH₃(HNCH₂CH₂OH) prepared in Example 9 and 3.82 g (13.44mmol) of Ti(O-iPr)₄. Thus, 5.05 g (90.66% yield) ofTi((CH₃)₃CC(O)CHC(NCH₂CH₂O)CH₃)₂ was obtained.

[0095] NMR results measured for the product are as follows:

[0096]¹H-NMR (199.976 MHz, CDCl₃) 5.18(s, 2H, C(O)CHC(N)),4.44-4.26(ddt, 4H, NCH₂CH₂O), 4.03-3.82 (ddt, 4H, NCH₂CH₂O), 2.00 (s,6H, C(N)CH₃), 0.92(s, 18H, (CH₃)₃CC(O)); ¹³C-NMR (50.289 MHz, CDCl₃)184.48(s, (CH₃)₃CC(O)), 168.87(s, C(N)CH₃), 97.01(s, C(O)CHC(N)),70.89(s, NCH₂CH₂O), 60.18(s, NCH₂CH₂O), 37.84(s, (CH₃)₃CC(O)), 28.04(s,(CH₃)₃CC(O)), 22.87(s, C(N)CH₃); EA (cal C: 57.97, H: 8.27, N: 6.76found C: 57.87, H: 8.63, N: 6.70).

Example 20 Preparation of Ti((CH₃)₃CC(O)CHC(NCH₂CH(Me)O)CH₃)₂,Ti(22dm2meih)₂

[0097] This Example was carried out according to the same procedure asin Example 11, using 4.0 g (20.06 mmol) of(CH₃)₃CC(O)CHCCH₃(HNCH₂CH(Me)OH) prepared in Example 10 and 2.85 g(10.03 mmol) of Ti(O-iPr)₄. Thus, 3.91 g (88.06% yield) ofTi((CH₃)₃CC(O)CHC(NCH₂CH(Me)O)CH₃)₂ was obtained.

[0098] NMR results measured for the product are as follows:

[0099]¹H-NMR (199.976 MHz, CDCl₃) 5.30, 5.28, 5.23, 5.19(s, 2H,C(O)CHC(N)), 4.91, 4.82 (m, 2H, NCH₂CH(Me)O), 4.16(dd, 1H,NCH_(ab)H_(cd)CH(Me)O), 3.98(dd, 1H, NCH_(ab)H_(cd)CH(Me)O), 3.77(dd,1H, NCH_(ab)H_(cd)CH(Me)O), 3.63(dd, 1H, NCH_(ab)H_(cd)CH(Me)O), 2.07,2.06, 2.04(s, 6H, C(N)CH₃), 1.22-1.14(d, 6H, NCH₂CH(CH₃)O), 1.02, 1.01,1.00, 1.00(s, 18H, (CH₃)₃CC(O)); ¹³C-NMR (50.289 MHz, CDCl₃) 185.12(s,(CH₃)₃CC(O)), 168.79, 168.46, 168.17(s, C(N)CH₃), 97.47, 97.00, 96.89(s,C(O)CHC(N)), 77.31, 76.80, 76.36(s, NCH₂CH(Me)O), 67.53, 66.95, 66.57,66.36(s, NCH₂CH(Me)O), 38.29, 38.22(s, (CH₃)₃CC(O)), 28.50(s,(CH₃)₃CC(O)), 23.13, 23.04(s, C(N)CH₃), 22.02, 21.18, 20.73(s,NCH₂CH(CH₃)O); EA (cal C: 59.73, H: 8.66, N: 6.33 found C: 59.44, H:8.78, N: 6.84).

[0100] Table 1 below shows representative examples and physicalproperties of the titanium precursors according to the presentinvention. Table 2 below shows representative examples and physicalproperties of various metal precursors (including a titanium precursorcommercially available from Asahi Denka Kogyo K. K., Japan) according tothe prior art. TABLE 1 Titanium Precursors of the Present InventionAbbreviated name Melting point Vaporization temp. Residue amount Formula(Example No.) (° C.) (° C.) (%)

Ti(eip)₂ ¹⁾(Example 11) 199 323 8.0

Ti(2meip)₂ ²⁾(Example 12) 199 290 <0.5

Ti(1meip)₂ ³⁾(Example 13)  61* 295 3.3

Ti(1deip)₂ ⁴⁾(Example 14) 235 290 13.7

Ti(1eeip)₂ ⁵⁾(Example 15) 149 303 7.6

Ti(pip)₂ ⁶⁾(Example 16) — — 26.6

Ti(26dm2meih)₂ ⁷⁾(Example 17)  185* 283 8.3

Ti(26dm1meih)₂ ⁸⁾(Example 18) 164 285 3.6

Ti(22dmeih)₂ ⁹⁾(Example 19) 180 307 10.6

Ti(22dm2meih)₂ ¹⁰⁾(Example 20) 218 287 0.5

[0101]¹) Ti(eip)₂: Titanium bis[4-(ethoxy)imino-2-pentano ate]

[0102]²) Ti(2meip)₂: Titanium bis[4-(2-methylethoxy)imino-2-pentanoate]

[0103]³)Ti(1meip)₂: Titanium bis[4-(1-methylethoxy)imino-2-pentanoate]

[0104]⁴) Ti(1deip)₂: Titanium bis[4-(1,1-dimethylethoxy)imino-2-pentanoate]

[0105]⁵) Ti(1eeip)_(2:) Titaniumbis[4-(1-ethylethoxy)imino-2-pentanoate]

[0106]⁶) Ti(Pip)₂: Titanium bis[4-(n-propoxy)imino-2-pentanoate]

[0107]⁷) Ti(26dm2meih)₂: Titaniumbis[2,6-dimethyl-5-(2-methylethoxy)imino-3-heptanoate]

[0108]⁸) Ti(26dm1meih)₂: Titaniumbis[2,6-dimethyl-5-(1-methylethoxy)imino-3-heptanoate]

[0109]⁹) Ti(22dmeih)₂: Titaniumbis[2,2-dimethyl-5-(ethoxy)imino-3-heptanoate]

[0110]¹⁰) Ti(22dm2meih)₂: Titaniumbis[2,2-dimethyl-5-(2-methylethoxy)imino-3-heptanoate] TABLE 2 MetalPrecursors of the Prior Art Melting point Vaporization Residue FormulaAbbreviated name (° C.) temp. (° C.) amount (%)

Ba(methd)₂ ¹⁾ Highly viscous liquid 391 8.3

Sr(methd)₂ ²⁾ Highly viscous liquid 389 3.1

Ti(mpd)(thd)₂ ³⁾ Highly viscous liquid 248 <0.5

Ti(OiPr)₂(thd)₂ ⁴⁾ 160 240 7

[0111]¹) Ba(methd)₂: Barium bis[1-methoxyethoxy-2,2,6,6-tetramethyl-3,5-heptanedionate]

[0112]²) Sr(methd)₂: Strontiumbis[1-methoxyethoxy-2,2,6,6-tetramethyl-3,5-heptanedionate]

[0113]³) Ti(mpd)(thd)₂: Titanium[2-methyl-2,4-dioxy-pentane]-bis[(2,2,6,6-tetramethyl-3,5-heptanedionate)]

[0114]⁴) Ti(O-iPr)₂(thd)₂: Titaniumbis(iso-propoxide)bis[(2,2,6,6-tetramethyl-3,5-heptanedionate)]

Measurement Method of Physical Properties

[0115] The physical properties set forth in Tables 1 and 2 were measuredby the following method: the melting point and vaporization temperaturewere measured from endothermic peaks of TG-DSC curves. However, thevalues indicated by the symbol * in Table 1 were measured by a meltingpoint-measuring device, because the heat absorption by vaporizationoccurred along with the melting of the precursors during themeasurement. The residue amounts were measured by thermal gravimetricanalysis (TGA) under atmospheric pressure (N₂, 20 ml/min) and recordedas residual weight of the precursors at 550° C.

Example 21 Moisture Proof of Precursor

[0116] 1.0 g of the precursor Ti(eip)₂ prepared in Example 11 and 1.0 9of the precursor Ti(2meip)₂ prepared in Example 12 were placed in vials,respectively, and left to stand in air for three months or more. Theanalysis by NMR of the precursors was then carried out. The NMR resultsshowed that there were no peaks of non-coordinated ligands and thatpeaks of the originally prepared precursors remained. It could be thusfound that the precursors according to the present invention were notsusceptible to moisture and also had excellent handling and storageproperties.

Example 22 Solubility of Precursor

[0117] To evaluate solubility of precursors required in introducing theprecursors in liquid phase for the deposition of thin films, theprecursor Ti(eip)₂ prepared in Example 11 and the precursor Ti(2meip)₂prepared in Example 12 were dissolved in methanol and n-butyl acetate,respectively. Results indicated that 0.5 g of the precursor Ti(eip)₂prepared from the ligand containing no asymmetric carbons was soluble in5 ml of methanol, but was insoluble in the same amount of n-butylacetate. In contrast, 0.5 g of the precursor Ti(2meip)₂ containingasymmetric carbons on its ligand was soluble in both methanol andn-butyl acetate. Moreover, the precursor Ti(22dm2meih)₂ prepared inExample 20 showed enhanced solubility over the precursor Ti(2meip)₂ by20%, due to a t-butyl group in its ligand. It could be accordingly foundthat the solubility of the precursors was influenced by the kind of R₁,R₂ and R₃ in the above formula (I) and that the presence of asymmetriccarbons in particularly R₁ and R₂ provided an increase in solubility ofthe precursors.

Example 23 Analysis of Thermal Property for Precursor

[0118] TG-DSC analysis for the precursor Ti(eip)₂ according to Example11 and the precursor Ti(2meip)₂ according to Example 12 was carried outunder atmospheric pressure in nitrogen gas or in air, and under areduced pressure (1.3 mbar) using Netzsch STA 449C equipment. In thisanalysis, the precursors were heated to 550° C. at a scanning rate of10° C./min in nitrogen gas of a flow rate of 20 ml/min, or in air of aflow rate of 30 ml/min. The results are shown in FIGS. 1a, 1 b, 2 a, 2 band 3.

[0119] By the TG-DSC analysis under nitrogen atmosphere, it could befound that the precursor Ti(2meip)₂ prepared in Example 12 melted at190° C. and completely vaporized at about 290° C. (see, FIG. 1b).Additionally, as seen in FIG. 3, by the TG-DSC analysis in air, theprecursor Ti(2meip)₂ was found to be thermally decomposed withexhibiting a strong exothermic peak at about 315° C. In this regard, theprecursor Ti(2meip)₂ is clearly distinct from the conventionalprecursors Ti(thd)₂(O-iPr)₂ and Ti(thd)₂ (mpd) that are thermallydecomposed with exhibiting a weak exothermic peak over a wide range oftemperature. This difference is due to that Ti(2meip)₂ has a relativelyweak Ti-N bond compared with a Ti-O bond and has a homoleptic structure.

[0120] Moreover, vaporization rates of the precursor Ti(2meip)₂ wascompared to that of the commercial precursors Ti(mpd)(thd)₂, Ti(thd)₂(O-iPr)₂, Ba(methd)₂ and Sr(methd)₂ The results are shown in FIG. 4. Itcould be found from FIG. 4 that Ti(2meip)₂ was low in their vaporpressure at the respective temperatures as compared to the commercialprecursors, so that it would be advantageous to ensure similarity invaporization property when forming a multi-component thin film with alow volatility metal, such as barium, or strontium, etc.

Example 24 Deposition of BST Thin Film by MOCVD Method

[0121] Using the precursor Ti(2meip)₂ prepared in Example 12 or thecommercial precursor Ti(mpd)(thd)₂, as a titanium precursor, andBa(methd)₂ and Sr(methd)₂, as barium and strontium precursors, thinfilms of (Ba_(x), Sr_(1-x))Ti_(y)O_(3-z) (BST) were deposited onsubstrates by a Liquid Source Metal Organic Chemical Vapor Deposition(LS-MOCVD) method. The substrates used in the deposition were planarsubstrates of Pt(1000 Å)/SiO₂(1000 Å)/Si and fine-patterned substrateswhere Ru is deposited on the patterns having an aspect ratio of 3(depth/width=0.45 μm/0.15 μm). The Pt film of the substrates wasdeposited by a sputtering method, and the Ru film by a MOCVD method.

[0122] As the liquid precursors, there were used two set of singlesolutions that had been prepared by dissolving the Ba, Sr and Tiprecursors in n-butyl acetate. For the preparation of the singlesolution, the precursors were used at Set I molar concentrations, i.e.,0.0093 M Ba, 0.0093 M Sr and 0.07999 M Ti(Ba: Sr: Ti=1:1:8.6), or Set IImolar concentrations, i.e., 0.0093 M Ba, 0.0093 M Sr and 0.04 M Ti(Ba:Sr: Ti=1:1:4.3).

[0123] An input flow rate of the liquid precursors was maintained at aconstant value of 0.05 g/min during the deposition of the BST thin filmby means of a Liquid MFC (error of ±0.002 g/min) from LintecInc.(Japan). To observe a trend of introduction of titanium into the BSTfilms according to a substrate temperature, the depositions were carriedout using the Set II solution in a temperature range of 400 to 500° C.For the depositions, MOCVD equipment was used in which a vaporizer, adeposition chamber and a gas delivery tube are all mounted in an oven.Additional process conditions are set forth in Table 3. TABLE 3 Processconditions Deposition pressure  1 Torr Flow rate of delivery gas N₂ 100sccm Flow rate of oxidizing agent O₂ 100 sccm Flow rate of N₂ introducedto 100 sccm deposition chamber Input flow rate of precursor 0.05 g/minsolution Temperature of substrate 400-500° C. Temperature ofvaporization 280° C. Temperature of precursor solution 280° C. deliverytube Temperature of volatile gas 150° C. delivery tube Deposition time 15 min

[0124] To analyze the contents of barium, strontium, and titanium in thethin film, the BST thin film deposited on the Pt film of the substratewas etched with a hydrofluoric acid (HF) solution, and thenquantitatively analyzed by Inductively Coupled Plasma-Atomic EmissionSpectroscopy (ICP-AES). The analytical results are shown in FIGS. 5a and5 b. As seen in FIGS. 5a and 5 b, if the commercial titanium precursorwas used, the titanium content was significantly dependent ontemperature, whereas if the titanium precursor according to the presentinvention was used, the titanium content was dependent on temperature toa reduced extent. Accordingly, it was found that the use of the priortitanium precursor made it difficult to control the titanium contentevenly between devices based on particularly large area substrates, orthe titanium content at the upper and lower portions of a high topologydevice. However, it was found that the use of the titanium precursoraccording to the present invention solved this problem relating to thetitanium content, because the temperature dependence of the titaniumcontent in the thin film was low.

[0125] Among the thin films deposited by the above method, the thin filmdeposited at 430° C. was subjected to various analyses. FIG. 6 is agraph showing X-ray diffraction (XRD) analysis results for the thinfilm. It can be found from FIG. 6 that a perovskite crystalline phasewas present in the BST thin film which had not been subjected toadditional heat-treatment following the deposition. FIG. 7a is a imagetaken by a scanning electron microscope for a slightly inclined plane ofthe thin film which was formed on the substrate at 430° C. As seen inFIG. 7a, the thin film had a smooth surface with no protrusions or hazyappearance. FIG. 7b is a image taken by an atomic force microscope (AFM)for the same thin film. FIG. 7b also supports the fact that the surfaceof the thin film is very smooth so that root mean square (RMS) roughnessis no more than 17Å. FIG. 8 is a cross sectional image showing the sideof the BST thin film which was formed on the fine-patterned substratehaving an aspect ratio of 3. From FIG. 8, it can be seen that the thinfilm had excellent step coverage. FIG. 9 shows analytical results bySecondary Ion Mass Spectrometry of the thin film. From FIG. 9, it can beseen that the thin film was very low in contamination with carbon ornitrogen atoms of the ligand.

[0126] Moreover, a planar MIM capacitor of a Pt/BST/Pt structure wasfabricated using the BST thin film which was deposited at 430° C. fromthe precursor Ti(2meip)₂ according to the present invention. Electricalproperties and dielectric properties for the fabricated capacitor weremeasured. Results are shown in FIGS. 10 and 11. As predicted from a XRDpattern of FIG. 6, the capacitor displayed the typical dielectricproperties of perovskite dielectrics in that capacitance was the highestat zero bias and decreased with an increase in the bias. Also, thecapacitor exhibited an excellent insulating property in that dielectricloss factor was less than 1% at an operation voltage of highlyintegrated DRAM devices, ±1V.

[0127] As is apparent from the foregoing, the group IV metal precursorsaccording to the present invention has volatility suitable for theformation of a thin film, as well as excellent thermal properties inthat it leaves little or no residues after being vaporized and in thatit is completely decomposed under an oxygen atmosphere. Furthermore, asthe group IV metal precursor according to the present invention has ahigh chemical stability, it causes no side reaction when being deliveredin the gas phase or used along with other precursors. Also, thisprecursor is not susceptible to moisture and hence requires no effortsfor storage and handling. The precursor according to the presentinvention leaves little or no residues of carbon or nitrogen,particularly when being used for the deposition of a multi-componentthin film, such as BST and the like. Further, using the titaniumprecursor according to the present invention, it is easy to control thetitanium content throughout a large area thin film or at the upper andlower portions of a high topology thin film. Thus, this precursorenables the formation of a high quality metal oxide thin film which isexcellent in step coverage and surface structure.

[0128] Although the preferred embodiments of the present invention havebeen disclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas disclosed in the accompanying claims.

What is claimed is:
 1. A tridentate ligand (L) having a charge of −2,which is represented by the following formula (I):

wherein each of R₁ and R₂, independently, is a linear or branched C₁₋₈alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group.
 2. Anorganometallic precursor of a formula M(L)₂ for use in the formation ofmetal oxide thin films, in which M is a group IV metal ion having acharge of +4 and L is a tridentate ligand of the following formula (I):

wherein each of R₁ and R₂, independently, is a linear or branched C₁₋₈alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group.
 3. Theorganometallic precursor according to claim 2, wherein the group IVmetal ion is a titanium ion.
 4. A chemical vapor deposition method whichcomprises forming a metal oxide thin film using, as a group IV metalprecursor, a complex of a formula M(L)₂ in which M is a group IV metalion having a charge of +4 and L is a tridentate ligand having a chargeof −2, the ligand being represented by the following formula (I):

wherein each of R₁ and R₂, independently, is a linear or branched C₁₋₈alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group.
 5. Thechemical vapor deposition method according to claim 4, wherein M is Ti.6. The chemical vapor deposition method according to claim 4, whichcomprises vaporizing the precursor by using of a bubbler or a vaporizer.7. The chemical vapor deposition method according to claim 4, in whichthe metal oxide thin film is a multi-component thin film containing agroup IV metal.
 8. The chemical vapor deposition method according toclaim 4, in which the metal oxide thin film is a multi-component thinfilm containing titanium.
 9. A metal oxide thin film formed by utilizingan organometallic precursor of the formula M(L)₂ in which M is a groupIV metal ion having a charge of +4 and L is a tridentate ligand having acharge of −2, the ligand being represented by the following formula (I):

wherein each of R₁ and R₂, independently, is a linear or branched C₁₋₈alkyl group; and R₃ is a linear or branched C₁₋₈ alkylene group.
 10. Theorganometallic precursor of claim 3, wherein said titanium precursor isselected from the group consisting of titanium bis[4-(ethoxy)imino-2-pentanoate], titanium bis[4-(2-methylethoxy)imino-2-pentanoate], titanium bis[4-(1-methylethoxy)imino-2-pentanoate],titanium bis [4-(1,1-dimethylethoxy)imino-2-pentanoate], titanium bis[4-(1-ethylethoxy)imino-2-pentanoate], titaniumbis[4-(n-propoxy)imino-2-pentanoate], titaniumbis[2,6-dimethyl-5-(2-methylethoxy)imino-3-heptanoate], titaniumbis[2,6-dimethyl-5-(-methylethoxy)imino-3-heptanoate], titaniumbis[2,2-dimethyl-5-(ethoxy)imino-3-heptanoate] and titaniumbis[2,2-dimethyl-5-(2-methylethoxy)imino-3-heptanoate].